Chromium-containing dyestuffs containing a monoazo and a diazo dyestuff



United States Patent CHROMIUM CONTAINING DYESTUFFS CONTAINING A MONOAZO AND A DI- AZO DYESTUFF Walter Biedermann and Eginhard Steiner, Basel, Switzerland, assignors to J. R. Geigy A.G., Basel, Switzerland No Drawing. Filed Dec. 16, '1964, Ser. No. 418,867 1 Claim. (Cl. 260145) ABSTRACT OF THE DISCLOSURE The chromium-containing azo dyestuif, which in its free acid form has the formula and dyes natural and synthetic polyamide fibers in brown shades of very good fastness properties.

The invention concerns a chromium-containing azo dyestuif which contains a mono and a disazo dyestuif bonded co-ordinatively to a hexavalent chromium atom. It also concerns a process for the production of this dyestufi and its use for the dyeing of natural and synthetic polyamide fiber materials such as wool, silk, leather, furs, nylons and the like, and also of super polyurethane fibers.

The novel dyestufi according to the invention 18 in its free acid form of the formula 3,374,219 Patented Mar. 19, 1968 and dyes the aforementioned fiber materials in brown shades which have very good all-round fastness properties, especially wet fastness, fastness to perspiration, sea water, alkaline and acid milling, and to cross-dyeing especially of nylon/wool blended fabrics, from acetic acid-acidified dyebaths.

Very surprising is the superior light fastness of dyestuifs according to the invention, particularly when compared to that of structurally most closely related known dyestuffs.

The dyestuif according to the invention is prepared in the following manner:

36.8 parts of the disazo dyestuif from diazotized 3- amino-4-hydroxyazobenzene and Z-hydroxynaphthalene, 22.4 parts of formamide, and 250 parts of water are mixed with the amount of complex chromium compound of the type 1 chromium atom to 1 dyestuif molecule, corresponding to 5.2 parts of chromium and 41.9 parts of the dyestuif 4-nitro-2-amino l-hydroxybenzene and 1-[3'-sulfophenyl]-3-methylpyrazolone. 10 parts of sodium hydroxide are added to this mixture which is then slowly heated to -95 and kept for 15 minutes at this temperature. The brown mass is then poured, while stirring well, into 200 parts of a 90-95 -hot 25 %-sodium chloride solution. The precipitated dyestuff is filtered off and dried. It is a brown powder which dyes wool, silk, leather and synthetic polyamide in brown shades of high grade fastness.

We claim:

1. The chromium complex dyestuif which in its free acid form is of the formula 220,140 2/ 1959 Australia. 342,307 12/ 1959 Switzerland.

FLOYD D. HIGEL, Primary Examiner. 

